Web Conference Summary of July 30, 2013 Technical Workshop on Case Studies to Assess Potential Impacts of Hydraulic Fracturing on Drinking Water Resources Rick Wilkin and Jeanne Briskin September 12, 2013 Office of Research and Development 1
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources Study Goals: • Assess whether hydraulic fracturing may impact drinking water resources • Identify driving factors that may affect the severity and frequency of impacts For more information: http:// www.epa.gov/hfstudy 2 2
Hydraulic Fracturing Water Cycle Recycling Facility Flowback and Disposal Produced Water Wastewater Well Treatment Plant Chemical Mixing Wellhead Drinking Water Treatment Plant Drinking Water Acquisition Water Well Ground Water Surface Water Aquifer Well Injection WATER CYCLE STAGES 3 Water Acquisition → Chemical Mixing → Well Injection → Flowback and Produced Water → Wastewater Treatment and Waste Disposal
Primary Research Questions What are the potential impacts on drinking water resources of: Large volume water withdrawals Water Acquisition from ground and surface waters? Surface spills on or near well pads Chemical Mixing of hydraulic fracturing fluids? Well Injection The injection and fracturing process? Flowback and Surface spills on or near well pads Produced Water of flowback and produced water? Wastewater Treatment Inadequate treatment of and Waste Disposal hydraulic fracturing wastewaters? 4
Retrospective Case Studies Purpose: To determine if drinking water contamination has occurred at the case study locations and, if so, identify possible sources of contamination • Washington County, PA • Bradford County, PA • Wise County, TX • Las Animas/Huerfano Counties, CO • Dunn County, ND 5
Las Animas/Huerfano Counties (Raton Basin), CO HF Target Formation • Coal Bed Methane (Vermejo & Raton Formations) Drinking Water Resources • Poison Canyon Formation and nearby underground sources of drinking water Research Focus • Ground water and surface water Sampling events • October 2011 • May 2012 • November 2012 • April/May 2013 6
Bradford County, PA HF Target Formation • Marcellus Shale Drinking Water Resources • Stratified drift & bedrock aquifers and surface water Research Focus • Ground water and surface water studies • Reports of methane in multiple drinking water wells Sampling events • October/November 2011 • April/May 2012 • May 2013 7
Washington County, PA HF Target Formation • Marcellus Shale Drinking Water Resources • Surficial & shallow confined aquifers and surface water Research Focus • Reported changes in drinking water quality • Reported methane in wells Sampling events • July 2011 • March 2012 8 • May 2013
Wise County, TX HF Target Formation • Barnett Shale Drinking Water Resources • Trinity aquifer and surface water Research Focus • Drinking water wells Sampling events • September 2011 • March 2012 • September 2012 • December 2012 • May 2013 9
Dunn County (Killdeer), ND HF Target Formation • Bakken Shale Drinking Water Resources • Killdeer aquifer Research Focus • Drinking water aquifer Sampling events • July 2011 • October 2011 • October 2012 10
Session 1: Retrospective Case Studies: Background Assessment and Characterization Participants considered two questions: 1. What are the relative strengths of different approaches to assess background conditions? 2. What are practical approaches to overcoming the challenges in developing a representative background assessment and characterization for a case study? 11
Session 1: Retrospective Case Studies: Background Assessment and Characterization Key Themes Approaches for assessing and characterizing background conditions Site-specific geochemistry and background data • Conceptual site models • • Site characterization to identify appropriate tracers and indicators • Quantitative “cut-points” rather than absolute values • Short- and long-term monitoring plans with defined objectives, sampling frequency, and parameters 12
Session 1: Retrospective Case Studies: Background Assessment and Characterization Key Themes Issues regarding background data Anthropogenic vs. background contamination • Importance of geochemistry • • Sample collection and analysis methods may be unknown- quality uncertain • Regional scales may be useful for identifying trends • Local scales may be useful for identifying impacts • Aquifer-specific (depth-related) background and water quality trends 13
Session 1: Retrospective Case Studies: Background Assessment and Characterization Key Themes Statistical approaches Averaged and pooled data may dilute signal • Historical data with "impacted" data may bias the signal • Stiff and Piper diagrams for graphical presentation of data • Aquifer-based analysis focused on individual cases • 14
Session 1: Retrospective Case Studies: Background Assessment and Characterization Key Themes Ground water contamination occurrence and exposure Indicators of water contamination • Cumulative exposure and exposure to mixtures of multiple • contaminants • Clearly define “impact” and how it relates to risk • Trace contamination to possible sources and provide context 15
Session 1: Retrospective Case Studies: Background Assessment and Characterization Key Themes Practical approaches for overcoming challenges Preliminary results from the U.S. DOE NETL studies with • tracers • Geochemical data analysis using appropriate techniques • Industry and university data may be useful if available • Collect distributed samples using approved methods • Case control design 16
Prospective Case Study Goals • Understand how site-specific hydraulic fracturing practices prevent impacts to drinking water resources • Evaluate any changes in water quality over time 17
Study Approach Follows development of production well Site Selection Baseline Monitoring Pad Installation / Well Drilling and Completion Hydraulic Fracturing and Flowback Management Oil and/or Gas Production 18
Site Selection Example environmental management practices conducted by well operator • Consider nearby water resources, slope, etc. Research Approach EXAMPLE GOALS ¡ EXAMPLE IMPLEMENTATION TASKS ¡ • New development area • Review historical oil and gas activities and distances • Relatively shallow ground water of good quality • Evaluate potential water quality impacts from • Nearby surface water resources with access for local pre-existing land uses monitoring • Determine distance and flow path to surface • Site topography provides good access for water resources monitoring wells • Identify existing nearby ground water wells • Cooperative landowners (access) • Gather pre-existing water quality information • Site visit to confirm • Sign access agreements ¡ 19
Baseline Monitoring Example environmental management practices conducted by well operator • Conduct water quality monitoring Research Approach EXAMPLE GOALS ¡ EXAMPLE IMPLEMENTATION TASKS ¡ • Install monitoring network • Determine depth, direction and rate of ground water flow • Conduct baseline monitoring • Drill, log and install monitoring wells at multiple • Document baseline water quality depths • Establish surface water monitoring locations • Conduct four quarterly water quality and flow monitoring events ¡ 20
Pad Installation / Well Drilling and Completion Example environmental management practices conducted by well operator • Install liners, construct berms • Install casing and cement, conduct mechanical integrity tests • Construct secondary containment for tanks/impoundments Research Approach EXAMPLE GOALS ¡ EXAMPLE IMPLEMENTATION TASKS ¡ • Document well construction details • Observe pad construction • Document well integrity • Observe drilling and completion of production well • Assess any impacts to water quality • Monitor ground and surface water for any impacts • Receive company-provided details on geology, casing materials and depths, cement details and evaluation tools, mechanical integrity test results, etc. ¡ 21
Hydraulic Fracturing and Flowback Management Example environmental management practices conducted by well operator • Choice of hydraulic fracturing fluid components • Fracture propagation assessment / microseismic monitoring • Pressure monitoring • Post-fracture mechanical integrity testing Research Approach EXAMPLE GOALS ¡ EXAMPLE IMPLEMENTATION TASKS ¡ • Document hydraulic fracturing and flowback • Observe hydraulic fracturing operations process • Monitor ground and surface water for any • Document fracture propagation impacts • Document pressure monitoring • Sample flowback • Document post-fracture mechanical integrity • Receive company-provided microseismic data; testing hydraulic fracturing reports on fluid volumes, pressure curves and chemical additives; • Assess any impacts to water quality mechanical integrity test results; etc. ¡ 22
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